President Trump, who said the process of choosing Kennedy's replacement would "begin immediately," now has the opportunity to further cement the court's conservative majority and shape its direction for decades to come.

Arizona-based oil investor and Republican fundraiser Dan Eberhart has soured on Trump's protectionist trade policies in recent months. But he said the vacancy — and the pitched battle to replace Kennedy — could galvanize conservative voters and help the party retain its threatened House majority.

Democrats need to flip just 24 Republican-held seats to seize control of the chamber.

"Speaker McCarthy just became a lot more likely," Eberhart told USA TODAY, referring to California Republican Rep. Kevin McCarthy, who could assume the No. 1 position in the House if Republicans prevail in November's election.

The looming confirmation battle over Kennedy's replacement already has galvanized Republican and Democratic activists. Conservative groups that came together last year for a $17 million campaign to confirm Justice Neil Gorsuch, Trump's first Supreme Court nominee, have prepped for months behind the scenes for this potential vacancy.

"This is the moment conservative women have been waiting for — the chance to return justice and constitutional limits to the nation's highest court," said Penny Nance, the president of Concerned Women for America.

She said the fight to confirm Kennedy's successor would be the "biggest and perhaps most important confirmation battle" in the group's nearly 40-year history.

The conservative Judicial Crisis Network, which spent $10 million to back Gorsuch, on Wednesday announced a seven-figure advertising campaign to target vulnerable Democrats in Congress and tout Trump's opportunity to "appoint another great justice."

Leaders of the influential political network aligned with conservative billionaire Charles Koch. meanwhile, say they would spend at least $1 million to back a conservative nominee and already have spent the last six months readying its base of more than 3 million activists around the country for the fight.

Sarah Field, the network's vice president of judicial strategy, said the Koch groups are prepared to run ads and send activists door-to-door.

Field told USA TODAY that Koch network is "comfortable" with all the names on Trump's list. "Our goal is to have a nominee that's in the mold of Justice Gorsuch," Field said, "somebody who's going to have fidelity to the Constitution, who won’t legislate from the bench.”

Whit Ayres, a veteran GOP pollster, said quickly confirming a new justice before the Nov. 6 midterms could prove crucial to Senate Republicans.

"It will make even more compelling the Republican argument that they have delivered on their promises and future control of the Senate is critical to accomplish conservative goals," he said.

On Wednesday, Senate Majority Leader Mitch McConnell, R-Ky., said the Senate would move quickly, promising a vote this fall on the nominee.

Senate Minority Leader Chuck Schumer, D-N.Y., said the Senate should not vote until after the midterms. He cited McConnell's refusal to allow a Senate vote on former President Barack Obama's nominee, Merrick Garland, in 2016. At the time, GOP leaders said the new president should get to pick the new justice.

Tom Steyer, a billionaire from California who is one of the Democratic Party's biggest donors, echoed Schumer's call.

Democrats, he said, "need to fight like hell to protect our democracy and ... prevent a nominee from getting a vote before the next Congress is seated."